Fans love to call for the invention of RoboUmp, but the humans are the ones well-versed in the baseball rulebook.

Most baseball fans feel they know the rules, but many of them are actually misunderstood, at least their nuances and technical definitions. Even you are fairly well-versed in the rulebook, a primer never hurts, so BP asked the MLB Umpiring Department about 10 of them. Major League Baseball umpire supervisor Charlie Reliford, a 19-year major-league umpire, and Major League Baseball umpire supervisor Larry Young, a 23-year major-league umpire, provided the definitions and clarifications.

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The Mets' fireballing setup man can hit 100 mph on the radar gun, but it's his improved slider that he hopes will give him an unstoppable arsenal.

When your fastball has been clocked as high as 102.5 mph, you don’t necessarily need a plus secondary pitch. Much to the chagrin of National League hitters, Bobby Parnell has one, and it is getting better. The Mets closer-in-waiting has been fine-tuning his slider, and the offering may be what takes him from overpowering to almost unhittable.

The 26-year-old right-hander was already no fun to face in 2010, as he logged an 8.4 K/9 and an even more impressive 4.1 K/BB out of the New York bullpen. Despite an abnormally high .374 BABIP, his ERA was a strong 2.83. He promises to be an even bigger challenge for hitters this year with an improved slider augmenting his heater.

Better and Better

“His breaking ball is getting better, as I think everybody will see,” said Josh Thole, who has established himself as the Mets' primary catcher. “Toward the end of last year he started becoming more aggressive with it, and this year I feel he’s refined it a little bit. You can see how it has improved.

“He gets good action on his slider, down and in to lefties,” continued Thole. “He can use it as his put-away pitch. When you throw that hard, having a put-away pitch that you can bury in the ground and get some swings and misses—it’s a great thing to have in your repertoire.”

According to Mets skipper Terry Collins, the pitch could be a difference maker for the hard-throwing right-hander.

“He’s got one of those special arms where late in the game he can do some damage,” said Collins. “But he doesn’t have to throw 100. He’s worked very hard to make sure that his secondary pitches are effective, and I think that will really help him.

“You have to have something that breaks. Against major-league hitters, you need something that moves, you can’t go just fastball, changeup. You have to get something that’s going to go away from some of these guys, or in to some of these guys, so I think the slider is a good idea for him.”

More and More

Parnell threw his slider just 15.7 percent of the time last year, a number that should increase markedly in 2011. While a pair of outings represents far too small a sample size to give a meaningful projection, PitchFX data shows that he has thrown 41.4 percent sliders to the seven batters he has faced this season. The pitch has averaged 84.3 mph, down from 87.3 last year, and the increased frequency at which it been used has been by design.

“I’m throwing my slider more and in different counts than what I was used to,” explained Parnell late in spring training. “I’m using it as a pitch to get ahead of hitters instead of just trying to strike them out with. In the past it’s been an 0-2, 1-2 pitch and now I’ll even use it on the first pitch of a count."

“I’m trying to throw strikes with it more consistently," Parnell continued. "It’s the same slider, I’m just starting it out in a different location in order to throw it for a strike. I’m not going to float one in and give them something good to hit, but in the same respect, I’m not going to throw one in the dirt. I need to find that happy median and throw the same pitch that I throw on 0-2, for a strike.”

While opposing hitters can expect to see more sliders from Parnell, they can mostly stop worrying about his changeup. He hasn’t completely scrapped it, but it won’t be seen often.

“My changeup is still there,” said Parnell, “but it’s more of a third pitch now. In my situation, having two good pitches is better than having three average pitches, so I’m focusing on fastball-slider. If I’m facing somebody who has seen me several times, my split-finger changeup is something I might pull out of my pocket, but only on occasion.”
Faster and Faster

Parnell averaged 96.4 mph with his fastball last season, hitting triple digits numerous times. Even with the improved slider, it remains his signature pitch, as only five hurlers threw it with a higher average velocity in 2010. Despite that, the flamethrower downplays the importance of his radar gun readings.

“Velocity really isn’t all that important,” opined Parnell. “It’s a side factor for me, I think, more than anything. I have to focus on location and pitch movement to be successful. Velocity comes secondary.

“My four-seamer is going to run a little bit in on a righty, and the more you can make it move, the harder it is on the hitter to see it and hit it. Movement is very important for me, more so than velocity.”

Thole doesn‘t necessarily disagree, but he knows what makes Parnell such an intimidating presence on the mound.

“His fastball is hard,” said Thole. “Not too many guys can say they throw 100 mph. When you’re throwing a heavy ball like he does, it makes it tough on the hitters. He throws a sinker, too, where he takes a little off his velocity, but when you’re throwing a sinker at 96 and then you can go up top at the letters with a 100-mph fastball, you’re going to get a lot of swings and misses. Then you add in the slider, and what you have is a guy you’d rather not face.”

Like most players in the minor leagues, Red Sox outfield prospect Che-Hsuan Lin is plugged in. He isn’t a gadget geek -- at least not yet -- but the 22-year-old native of Taiwan certainly knows his way around cyberspace, especially when it comes to staying in touch with the other side of the world. Lin is beginning the 2011 season with the Double-A Portland [Maine] Sea Dogs, over 7,600 miles from home.

Aaron Hicks is poised to take an aggressive step forward this summer. The 21-year-old outfield prospect has the highest ceiling of any player in the Twins system, and while he has yet to have the breakout season many have been predicting since he was drafted 14th overall in 2008, it may be about to happen. A big reason is a new approach, which adds aggression to his disciplined nature.

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There is more to Bobby Jenks than the scary beard [is there a better way to describe it?] and much-publicized spring tiff with Ozzie Guillen. There is also more than the fastball, as the new addition to the Red Sox relief corps has evolved from a flame-throwing wild man into more of a craftsman. The erstwhile ChiSox closer hasn’t exactly turned into Greg Maddux—he still intimidates hitters with mid-90s heat and his mountain-man physique—but he incorporates a five-pitch mix into his attack plan.

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Andrew Miller is an enigma getting another chance. Just how many more he’ll get, or needs, remains to be seen, but it is notable that the flame-throwing southpaw is only 25. Given all he has been through, you’d be excused for thinking he is older.

Though the versatile fielder isn't a star, he brings more than just defensive flexibility to the table.

Don Kelly may well be the most valuable spare part in the American League. Reminiscent of Tony Phillips, the Tigers super-utilityman provides excellent versatility to Detroit’s roster, having seen time at seven different positions in his brief big-league career. He is expected to add an eighth this summer, and it is that versatility that makes him an asset. Since breaking in with the Pirates in 2007, Kelly has appeared in 84 games in left field, 30 at first base, 19 at third base, 12 in center field, five in both right field and shortstop, and four at second base.

David Freese, Colby Rasmus, and Mark McGwire discuss their approaches to hitting.

David Freese and Colby Rasmus will play key roles for the Cardinals this year, as will their hitting coach, Mark McGwire. Both players will be counted on to provide offensive punch, while Big Mac will be entrusted to help the young sluggers surpass their 2010 production. Rasmus is coming off a season where he hit .276/.361/.498 with 23 home runs. Freese hit .296/.361/.404 with four home runs before having his rookie campaign derailed by an ankle injury after just 80 games.

With a spot secure in the Twins' rotation, Duensing discusses his pitch repertoire, BABIP, and sequencing.

Brian Duensing is out to prove that his 2010 season was a sign of things to come and not a luck-influenced anomaly. The 28-year-old southpaw began last year in the Twins’ bullpen, only to move into the starting rotation after the All-Star break and impress to the tune of an 8-2 record in 13 starts. He was no less effective as a reliever, as his overall totals included a 10-3 record and a 2.62 ERA in 53 appearances. It was a heady first full big-league campaign, but two numbers offer a cautionary tale going forward: a .272 BABIP and a 5.37 K/9 rate.

In a perfect world, Yasmani Grandal will one day become the Queen City’s version of Jorge Posada or Ted Simmons, but with the added bonus of above-average defense. The potential is there, but for now the switch-hitting backstop is an unproven 2010 draft pick in his first big-league camp.

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Last weekend's MIT Sloan Sports Analytics Conference featured a multitude of insiders and big names, but not all of the thought leaders on hand were as well-know and influential as Mark Cuban, Malcolm Gladwell and Jeff Moorad. The conference also included research paper track presentations, which gave MBA candidates like Greg Rubin an opportunity to display their analytic skills and ideas. Rubin, who attends New York University’s Stern School of Business, sat down with BP to give an overview of his paper, “Paired Pitching: How to Avoid an Arms Race.”